Automatic brake.



No. 875,543. PATENTED DEC. 31, 1907. J. LYNCH. AUTOMATIC BRAKE.APPLIOATION FILED JUNE 29 1907 2 SHEETS-SHEET 1.

No. 875,543, PATENTED DEC. 31, 1907. J. LYNCH.

AUTOMATIC BRAKE- APPLICATION FILED JUNE 29 1907.

2 SHEETS-SHEET 2.

R m ma W W M N W W JAMES LYNCH, OF VAN BUREN, ARKANSAS.

AUTOMATIC BRAKE.

Specification of Letters Patent.

Patented Dec. 31, 1907.

Application filed June 29,1907. Serial no. 381,477.

To all whom it may concern:

Be it known that I, JAMES LYNCH, a citizen of the United States, and aresident of Van Buren, in the county of Crawford and State of Arkansas,have invented a new and Improved Automatic Brake, of which the followinga full, clear, and exact description. This lnvention relates toautomatic brakes,

.and the object of the invention is to produce .a brake of this classwhich is simple in construction and which can be controlled initsoperation by pneumatic means.

More specifically, the purpose of the invention is to provide a brakewhich'is held unapplied by the air ressure in the service pipe, butwhich is applied by spring pressure when the pressure in the servicereduced.

The invention consists in the construction and combination of parts tobe more fully described hereinafter and particularly set forth in theclaims.

Reference is to be had to the accompanying drawings forming a part ofthis specification, in which similar characters of reference indicatecorresponding parts in all the figures. V

Figure 1 is a plan of the brake mechanism at one end of a car, the bodyof the car being "indicated by dotted; lines, and the brakebeingoperated by my invention; Fi 2 is a longitudinal central sectionthrougii the air cylinder and s ring box, which constitutes a feature ofti? an end view of the air cylinder, that is, it is a View of the leftend of the mechanism shown in Fig. 2; and Fig. 4 is an elevation of theoppositeend of thedevice shown in Fig.2.

Referring more particularly to the parts, 1 indicates the car body indotted lines. Near the middle portionof the car body at the pipe issufficiently usual point where the brake cylinder is applied, I attach abracketplate 2, to which my air chamber and spring box 3,is attached.

This air chamber and spring box is clearly shown in Fig. 2. It comprisesan air cylinder 4 provided with a head 5 at one end, having an airnipple 6 through which the air sup plied to the cylinder passes into theinterior thereof, as shown. Within this air, cylinder there is slidablymounted a piston head 7, and on the face of this head adjacent to thenipple 6, I provide a longitudinally projecting stem 8, the extremitywhereof is slightly tapered as shown. The piston head 7 is e invention;Fig. 3' is suitably I a'cked so as to prevent leakage of air past t ehead, and it is attached to a piston rod 9 which extends longitudinallyin a cylindrical spring box 10 wh1ch is bolted to the end of thecylinder 4 as indicated. This spring box or spring barrel has the sameinternal diameter as the air cylinder or chamber 4, and within whichthere is provided a helical spring llyone end of wh1ch thrusts againstthe side ofthe head 7, while the other'end thrusts against a fixed head12 which screws upon the remote end. of the spring barrel as shown. Thepiston rod 9 extends through the head 12, and'is provided at itsextremities with threads 13 which facilitate its attachment toone of themain brake levers 14. This brake lever is connected by a link 15 with asimilar brake lever 16 which has a fixed fulcrum at the point 17 on thebracket plate 2. The ends ofthese levers 14 and 16 are connected withlinks 18 which operate to apply the brake shoes 19 of the usualequalizing mechanism 20, illus- 'trated at the right in Fig. 1.

The nipple 6 is supplied with air through a branch pipe 21 leading fromthe train service pipe 22 as shown. It will be understood from an insection of Fig. 2, that the spring 11 constant y tends to pull the pistonrod 9 into the spring barrel, which will apply the brakes, The "airpressure existing in the train service pipe exists also in the aircylinder, so that the head 7 isnormally held in the end'of the cylinderremote from the nipple 6. In this way the spring 11 is held in acompressed condition, and the brakes are maintained una'pplied'. Whenthe pressure in the train service pipe is reduced, as is usual inapplying the brakes when pneumatically operated, the spring 11 extendsitself and ap lies the brakes.

n order to prevent too sudden an action of the spring in case the airhose should burst and the pressure in the service pipe be suddenlyreduced to 'zero, I provide the stem 8, which has been referred toabove. It will be observed that as the piston 7'moves toward the left,the end of the stem enters the bore of the nipple 6, and in this way theoutward flow of the air. through the nipple forced out by theadvancing-piston becomes choked. In this way I cushion the piston, whenthe spring suddenly applies the brakes, and thus I prevent anypossibility of throwing out the head 5 ,or of injuring the brakemechanism VVhenthe cars are being shifted around the railroad yard andat other times, if necessary, the brakes of any car can be heldunapplied by means of a-trans'verse pin 23 indicated in dotted lines inFig. 2, which is removably received in a suitable opening through thepiston rod 9. When this pin is in position it 'acts as a stop restingagainst the end of the barrel to hold the spring back.

Having thus described my invention, I claim as new and desire tosecureby Letters Patent:

'1. In a brake mechanism, in combination;

an air cylinder, a piston working therein, a

ing the said spring tending to move said piston within said cylinder toapply the brakes, means for admitting air to said cylinder to oppose theforce of said spring, and means-for cushionpiston'when the-brakes aresuddenly applie 2. In a brake mechanism, incombination, an air cylinder,a piston moving therein, a spring plressing said piston toward the endof said'cy 'nder and affording means for applyin the brakes, and meansforchoking the efflux ofair from said cylinder when said spring advancessaid piston.

v 3. In a brake mechanism, in combination, an air cylinder, a pistonworking therein, and carrying a longitudinally disposed stem on theforward side thereof, said-cylinder having a head with an openingthrough which the air may escape in alinement with said stem,

and a spring forcing said piston toward said head and afiording meansfor applying the brakes, said stem aifording means for choking the flowof air throughsaid opening as said piston advances! 4. In abrake'mechanism, in combination,

- an air cylinder, a piston working therein and carrying alongitudinally disposed stem, said cylinder having a head with a ventopenin therein through which air may escape, said vent opening bein inalinement with said stem whereby it wi lbe choked by said stem when saidpiston is adjacent thereto, a spring forcing said piston toward saidhead and affording means for applying the brakes, and

means independent of the air pressure for holding said piston againstpmevement by said spring.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses:

JAMES LYNCH. Witnesses:

SAM R. CHEW, 'OVERTON M. PARKS.

